In general the determination of the frequency content of an FM
waveform is complicated, but when

is small, for a sinusoidal
signal

, the bandwidth of the FM signal is

On the other hand when

is large, the bandwidth is determined
(empirically) to be

Your FM dial goes from 88 MHz to 108 MHz (this range is in between the
frequency ranges for the TV channels 1-6, and 7-12.
For a typical radio station,

varies from about 150 at low
frequencies like 50 Hz
to 3.75 at high frequencies (20 KHz), and a very rough bandwidth
figure is 200 KHz. Thus, KDFC 102.5 on your FM dial goes from
102.4 MHz to 102.6 MHz.